Collaborative Research: Genetic diversity, resistance genes, and negative density dependence in tropical tree seedling dynamics

合作研究：热带树木幼苗动态中的遗传多样性、抗性基因和负密度依赖性

• 批准号: 1457515
• 负责人: Liza Comita
• 金额: $ 15.85万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457515&HistoricalAwards=false
• 关键词: Collaborative; Research; Genetic; diversity; resistance

Tropical forests are famous for their high diversity, as well as the large number of rare species they harbor. Recent studies have found that, compared to common species, rare tropical tree species suffer more from pathogens that are specialized to a single host species that then spread rapidly through dense patches of seedlings of that single host. This research will test the novel hypothesis that rare species are more strongly impacted by host-specific pathogens because they have lower diversity of resistance genes at the population level, such that all their seedlings will be susceptible to the same suite of pathogens, promoting rapid pathogen spread and increasing mortality rates. This hypothesis will be tested using experimental greenhouse and field studies, combined with genetic analyses that will quantify the diversity of resistance genes for rare and common tree species in lowland tropical forest on Barro Colorado Island, Panama. Computer simulations will also be used to examine whether the measured differences in resistance gene diversity would impact infection levels, mortality rates and local abundance of tree species. Results of this study will improve understanding of plant-pathogen interactions, with potential applications for agriculture and horticulture (e.g. increasing pathogen resistance in crops). Hands-on training in cutting-edge genetic techniques would be provided to a wider audience through a summer workshop for students and faculty.This study will be the first to obtain large transcriptome datasets from a tree community and will provide gene sequence data that will be informative for future studies of genetic diversity in tropical forests. Examination of the effects of resistance gene diversity on forest dynamics will bridge the gap between molecular evolution studies that indicate ongoing selection for multiple resistance genes at many loci, and how this diversity functions in nature. Furthermore, this study is likely to bridge competing theories for tropical plant diversity by providing a genetic explanation for why rare tree species are more strongly controlled by their species-specific enemies, while simultaneously supporting dispersal limitation as a feature determining which species are locally dominant. Ultimately, the study should elucidate whether local rarity restricts local genetic diversity, which in turn reinforces local rarity, a cycle that can be escaped only by recruitment of new alleles via long-distance pollen or seed movement. Demonstrating such a coupling between the ecological and genetic features of populations would bring new perspectives and avenues for theoretical advances in evolution and ecology. The project will provide research experiences for undergraduate and graduate students, as well as a postdoctoral researcher.

热带森林以其高度多样性以及它们藏有的大量稀有物种而闻名。 最近的研究发现，与常见物种相比，稀有的热带树种遭受了病原体的影响，这些病原体专门针对单个宿主物种，然后通过该单一宿主的幼苗迅速传播。 这项研究将检验一个新的假设，即稀有物种受宿主特异性病原体的影响更大，因为它们在人群水平上具有较低的抗药性基因的多样性，因此它们的所有幼苗都会容易受到相同病原体套件的影响，从而促进快速病原体的传播和增加死亡率。 该假设将使用实验性温室和现场研究进行检验，并结合遗传分析，这些分析将量化Panama Barro Colorado岛低地热带森林中稀有树种和常见树种的抗性基因的多样性。计算机模拟还将用于检查抗性基因多样性的测量差异是否会影响感染水平，死亡率和树种的局部丰度。这项研究的结果将提高对植物病原体相互作用的理解，并在农业和园艺中使用潜在的应用（例如，农作物中的病原体耐药性增加）。通过夏季研讨会为学生和教师提供尖端遗传技术的动手培训。这项研究将是第一个从树木社区获得大型转录组数据集的研究，并将提供基因序列数据，这些数据将为您对热带森林中遗传多样性的未来研究提供信息。对抗性基因多样性对森林动力学的影响的检查将弥合分子进化研究之间的差距，这表明许多基因座的多种抗性基因的选择以及这种多样性在自然界中的作用。此外，这项研究很可能通过提供遗传解释来弥合热带植物多样性的竞争理论，以说明为什么稀有树种更受其物种特异性敌人的强烈控制，同时同时支持分散限制作为确定哪些物种局部优势的特征。最终，该研究应阐明局部稀有性是否限制了局部遗传多样性，而局部遗传多样性又加强了局部稀有性，这一周期只能通过长距离花粉或种子运动来募集新等位基因。展示人口的生态和遗传特征之间的这种结合将为进化和生态学的理论进步带来新的观点和途径。该项目将为本科生和研究生以及博士后研究员提供研究经验。